WPS: Fix hostapd reconfig to update WPS UPnP string pointers

WPS: Fix hostapd reconfig to update WPS UPnP string pointers

This is needed to update the pointers maintained within WPS code
to use the new configuration data instead of maintaining pointers
to the old configuration which will be freed. This fixes strings in
UPnP discovery after reconfig (they used to be random freed memory..).